The gray crescent
A) is observable in the frog zygote.
B) develops at the site of sperm entry.
C) causes rotation of the cortical cytoplasm.
D) induces formation of the optic cup.
E) is induced by Sonic hedgehog proteins.

Question

Quizplus · Accepted Answer

The gray crescent is a band of cytoplasm located on the opposite side of the point where the sperm enters the egg. It is observable in the frog zygote and it is important in embryonic development as it contains the dorsal determinants, which initiate the formation of the dorsal-ventral axis.

The Gray Crescent